Small (average of 15 full-time staff members), under-resourced organizations that comprise the outpatient substance abuse treatment (OSAT) system provide most drug abuse treatment in the United States. Implementation of the Patient Protection and Affordable Care Act (PPACA) of 2010 will dramatically change the organizational environment for these organizations. Regardless of the outcome of the constitutional challenge to PPACA, the expansion of Medicaid, the development of Health Insurance Exchanges and the mandate to include substance abuse treatment in essential benefits packages will greatly expand the number of Americans whose health insurance covers OSAT services and thus alter the payer mix in OSAT programs. The emphasis on integrated models of care, including patient-centered medical homes and Accountable Care Organizations, creates incentives for care coordination. These reforms will generate sweeping changes in the financing, organization and accessibility of OSAT care. The proposed study applies open systems and resource dependence theory to examine two major aspects of health reform - the expansion of insurance and incentives for integration of substance abuse treatment with mainstream health care - that are likely to influence OSAT programs' organizational responses (i.e. use of technology, staffing, affiliations and alliances) as well as the accessibility and quality of drug abuse treatment. That said, the PPACA faces legal, political, fiscal, and implementation uncertainties. Organizational theory suggests that such uncertainties will increase OSAT programs' concerns about obtaining resources necessary for functioning and survival, leading to closer alignment and mergers among organizations. The proposed study will explicitly model this environmental uncertainty as a moderator of OSAT organizational responses. We will survey a nationally-representative sample of 500 OSAT programs in summer 2013 to examine the extent to which OSAT programs are acting in anticipation of the new organizational environment. We also propose semi-structured interviews with the directors of the 50 single-state agencies for substance abuse treatment and in-depth qualitative interviews with key legislative stakeholders to assess state preparations and anticipatory changes from the PPACA. By re-surveying the 500 OSAT programs in winter 2015 we will determine the post-implementation impact of the PPACA on OSAT organizational responses and service delivery. A panel data set will be formed by linking the survey and interview data to data from the National Drug Abuse Treatment System Survey (NDATSS) collected during 2000 and 2005, which will provide a true baseline of OSAT programming and services prior to enactment of both the PPACA and the Mental Health Parity and Addiction Equity Act of 2008. This study will enable us to examine the impact of health reform on the nation's OSAT system and provide high-quality information to policy makers and stakeholders to evaluate the effectiveness of the PPACA in improving the accessibility and quality of substance abuse treatment. 1